Facsimile system



Feb. 17, 1931. F, ME 1,792,767

FAGS IMILE SYSTEM Filed Nov. 50, 1928 INVENTOB FRiTZ SCHROTER J4 .4 4 ATTO EY Patented Feb. 17, 1931 UNITED STATES PATE NT ol-"rlca FRITZ SCHROTEB, OI BERLIN, GERMANY, ASSIGNOB '10 TELEI'UNK EN GEBELLSCEAF'J. FUR DRAH'ILOSE TELEGBAPHIE M. B. H., OF BERLIN, GERMANY, A CORPORATION 01 GERMANY Application filed November 80, 1928, Serial Io.

' By mycopending application, Serial No. a 286,617, filed June 19, 1928, I have disclosed a method adapted ,to explore and recompose pictures as has been disclosed according to which several picture lines which are explored and recorded or recomposed' consecutively as to time, are not directly adjacent to each other as regards space or geometrical location.

In the followin specification one form of this method whic is readily practicable is described- Various means suitable for carrying out the invention, as applied to different cases of picture transmis'sion,are illustrated by the accompanying drawing, wherein Fig. 1 illustrates the use of the invention in connection with a drum type of transmitter of known kind; while Fig. 2 disclosed a receiver based upon an arrangement adapted to transfer received signs or signals upon a continuous telegraphic strip or band into facsimile in a manner such that the spots of light pass over the tape at right angles to its direction of its line by line motion.

The fundamental idea of the invention is that for the photoelectric picture exploration at the sending end, and for the photographic picture recording or recomposition at the receiving end, several alternating luminous spots having different locations or situations are provided. One modification of this scheme inside the scope of this invention I would consist in that the luminous spots may be replaced by other equivalent recording means of known type, whenever recording other than by photography is resorted to in receiving and reproducing a picture.

In what follows, the considerations shall,

- however, be confined to devices working with 'tion ofthe outgoing picture,

Now making re rence to the drawings, and particularly referring to Fig. 1, 1 deracsmrmz: sx'srmm 822,785, and in Germany December 18, 1827.

picture or the like, is immaterial in this instance, The pictured drum 1 is revolvable about spindle 3 while it is" at the same time shifted axially in the direction of the arrow 5 a small distance during each rotation so as to insure exploration along a helical or spiral line. .The shifting action is insured by a driving member or tappet 4 in a manner similar to that used in schemes previously well known in the art and disclosed, for example, by many previously granted United States patents, of which Nos. 888,098 and 1,699,222 may serve as examples.

The drum or cylindrical surface, according to the invention, is explored by three light spots 14, 15, 16 suitably located at equal distance from one another in constant alternation by the reflection method by the aid of the annular or similarly formed photo-. electric cell 6, and the rays are so directed as to pass throu w h the inner hole thereof. For this purposetiere are employed three sources of light 8, 9, 10 or three parts of one and the same light source, say, the incandesced spiral of what is known in the art as a nitralamp (nitrogen-filled bulb), small portions of which are allowed to passthrough apertures inthe dia hra 11 and being reproduced through 0 jective 7- upon-the drum-shaped surface in the form of luminous spots 14, 15 and 16. In order to introduce a carrier frequency for thepicture signals, a perforated.

or slit disk 12 may be mounted in well known manner in the ath of the rays so as to rapidly interrupt the i ht rays at the desired frequency. In or er to make sure that upon each revolution only one of the three light spots 14, 15, 16 will be made to operate, there is provided a uniformly. rotating or intermittently moved diaphragm 1 3 which may be designed in various ways, for example, as a I slit disk or slit drum. A similar diaphragm,

' at the sending end;

.55 also for any other number of light spots, 1

Suppose now, for example, that the picture (irrespective of what kind or type it may be) occupies the shaded portion marked 2 of the drum surface. In the position, as shown, the luminous point 16 just touches the edge of the field of the picture, while the light spots 15 and 14 are still in the unused zone 2 of the drum '1. The distance between the three light spots 14, 15 and 16, of course, can be varied within wide limits, according to the requirements of reception, that is, according to the periodicity of the fading phenomena.

In the case here dealt with it shall be chosen at a value equalling the width of 10 lines on the outgoing picture.

From the beginning of a transmission, spot 1.6 thus will consecutively write the first, the fourth, the seventh and the tenth line, etc., While spots 14 and 15 for the time being do not participate in the transmission. Since by action of the moving diaphragm 13, spot 16 is operative only every thirdline, there remains first a space comprising two unexplored lines, namely, lines 2, 3, 5, 6, 8, 9, etc. If, then, owing to the axial shift of the picture drum in the direction of the arrow 5 the edge of the picture has reached the zone of spot 15, this spot begins to explore lines 2, 5, 8, '11, etc. After another interval of time of the same length, also spot 14 .begins to take part in the transmission, this spot exploring lines 3, 6, 9, 12, etc; This can be easily accomplished by the proper adj ustment of the distance. between the luminous spots. It will be seen that in this scheme no line will beexplored twice or be recomposed or recorded twice at the receiving end, and further that never the two neighboring or contiguous lines of a given line will be explored or recorded immediately before or after it, indeed, that relatively long intervals of time between these actions; are inserted. The total duration of transmission of the whole picture zone 2' in this arrangement is only increased by the' slight amount which corresponds to the conveyance of the drum by the width of zone lVhat has been said above respecting three light exploring spots naturally holds good provided the number is chosen so as to be suited for the conditions. As a rule, however, two or at most three light spots will sufiice.

Now referring to Fig. 2 the identical process for 'a continuously operating facsimile telegraph recorder has been illustrated and for simplicity of illustration has been ex 'hibited as' the receiving end of the system. The photographic film or paper strip or tape guided over the rolls 19 and is passed in the direction of the arrows 20 through the light exploring zone or the recording zone by a driving mechanism which is operated in synchronism with a similar mechanism at the sending end. Also, in this case, the light spots are designated by 14, 15, 16, and they are alternated by the diaphragm 17 which may consist, for example, of a revolving slit drum or an intermittently moving diaphragm of suitable shape. The transverse movement of the light spots, that is, at right angles to the strip 18, as will be seen, is insured parallel to the axes of the guide rolls 19. The'particular ways and means adopted to secure synchronism and proper phase relations between this motion at the transmitter and receiver ends is immaterial in this connection.

The guidingof the telegram strip is so constructed that the lower pair of rolls 19 is adapted to be shifted or adjusted byvery small and accurately adjustable amounts so that, if the-strip is under sufiicient tension, the adjustment of the lines covered by the spots 14, 15, and '16 can be insured in the sense of this invention, that is to say, the

spots describe lines of different order in such a way that a line is never repeated in exploring or recording. To be sure, it is entirely possible and permissible to, cause the lines to overlap more or less in order that the photographic light-marks by the integration of repeated blackening.- may be brought out more clearly and to make them thus more readily distinguishable from at:- cidental stray marks or. impressions. By the suitable selection of the length of strip between two light spots a sufficient time interval in the exploration and the recording between contiguous transversal lines is provided. I

Having now described my invention, what I claim is:

1. The method of picture decomposition and recomposition which includes directing a plurality of light rays separated by predetermined amounts toward a record surface, and alternately and successively changing the decomposition and recomposition of the picture from one to anotherof the plu rality of rays. 7 I

2. The method of picture decomposition and recomposition which includes directing a plurality of light rays toward a record surace, separating the'individual rays by pre determined amounts, and alternately and successivel' changing from one to another of ow on elemental areas of the'picture to be transmitted into electric currents-of propor- 'vidual scanning rays by pre tionate strength, continually and successively changing the light conversion into varyin strength currents in'accordance with said di ferent rays of light, and separating the successive scanning rays by predetermined amounts so as to scan adjacent lines of the picture surface at relatively wide time intervals. I

4. In a facsimile transmitting system, a plurality of light sources for directing scanning rays toward a picture surface to be transmitted, means for separatin the indidetermined amounts, and means for alternately and successivel illuminating the picture to be trans- 'mitted y said several scanningrays for analyzing the varying intensities of light and shadow on elemental areas of the picture surface.

5. In a facsimile transmitting system having a support surface for carrying the record to be transmitted, a lightsource for directing scanning rays toward the record support surface, a diaphragm for separating the individual scanning rays by predetermined amounts, and a second diaphragm for successively changing the illumination of the record surface from one to another of the plurality of scanning rays.

6. In a facsimile transmitting systemhaving a support surface for carrying the record to be transmitted, a source of light for illuminatin the record, means for separating the Y illuminating light into a plurality of separated paths, means for alternately and successively limiting the illumination of the record surface to a single light path at any 10. A facsimile system including a support surface for a facsimile to be transmitted,

means for directin a plurality of spaced light rays against t e supported picture surface for scanning the source, a photo cell for converting varying intensities of light and shade in the facsimile into electric current impulses, means for continually and successively influencing the photo cell from the varying intensities of light and shade in the picture surface as reflected by said light rays impinging thereon, and means for directing said light rays to said picture in such a manner that adjacent lines are scanned at relatively great time intervals.

11-. A picture transmission system, including, a drum for supporting a picture to be transmitted, means for rotating said drum and continually shifting the same axially dur-' mg1 its rotation movement, a plurality of lig t sources for directing scanning light rays upon the picture surface carried by said drum member, means for separating the various point where said light rays strike said picture surface, whereby the separate points are separated by a relatively great distance, photoelectric means for converting varying intensities of light and shade in the picture surface.

as exhibited in the reflected rays from said light source reachin said picture surface into varying strength e ectric current impulses,

and means for continually and successively changing the influence of said photo cell from one to another of said light rays, whereby successive scanning paths of said picture take place at widely separated time intervals due to the spacing of said light rays.

FRITZ SCHROTER.

instant, and light responsivemeansfor converting the'varying intensities of light and shadow on the record surface as determined 'by the illumination means into proportionate 'strength electric currents.

ing in addition means for controlling the separation of the plurality of light paths in such manner that the successive paths may I be made to slightly overlap.

9. A facsimile transmitting system including a support surface for a icture to be transmitted, a plurality of lig t sources for directing scanning rays to the supported picture surface, means for separating said individual scanning ra s b a predetermined amount, and means or a ternately and successively changing from one to anotherof said scanning rays for analyzing the varying intensity of light and shade in the picture surface. 

